Trouble Diagnoses - How to Perform Trouble Diagnoses for Quick and Accurate Repair (Cont'd) - Intermittent Problem Simulation
EF & EC-36prose procedureHow to Perform Trouble Diagnoses for Quick and Accurate Repair (Cont'd)
INTERMITTENT PROBLEM SIMULATION
NOTE
In order to duplicate an intermittent problem, it is effective to create similar conditions for component parts, under which the problem might occur.
Perform the activity listed under Service procedure and note the result.
1
Variable factorMixture ratio
Influential partPressure regulator
Target conditionMade lean
Service procedureRemove vacuum hose and apply vacuum.
1
Variable factorMixture ratio
Influential partPressure regulator
Target conditionMade rich
Service procedureRemove vacuum hose and apply pressure.
2
Variable factorIgnition timing
Influential partCrank angle sensor
Target conditionAdvanced
Service procedureRotate distributor clockwise.
2
Variable factorIgnition timing
Influential partCrank angle sensor
Target conditionRetarded
Service procedureRotate distributor counterclockwise.
3
Variable factorMixture ratio feedback control
Influential partExhaust gas sensor
Target conditionSuspended
Service procedureDisconnect exhaust gas sensor harness connector.
3
Variable factorMixture ratio feedback control
Influential partControl unit
Target conditionOperation check
Service procedurePerform self-diagnosis (Mode II) at 2,000 rpm.
4
Variable factorIdle speed
Influential partA.A.C. valve
Target conditionRaised
Service procedureTurn idle adjusting screw counterclockwise.
4
Variable factorIdle speed
Influential partA.A.C. valve
Target conditionLowered
Service procedureTurn idle adjusting screw clockwise.
5
Variable factorElectrical connection (Electric continuity)
Influential partHarness connectors and wires
Target conditionPoor electrical connection or improper wiring
Service procedureTap or wiggle. Race engine rapidly. See if the torque reaction of the engine unit causes electric breaks.
6
Variable factorTemperature
Influential partControl unit
Target conditionCooled
Service procedureCool with an icing spray or similar device.
6
Variable factorTemperature
Influential partControl unit
Target conditionWarmed
Service procedureHeat with a hair drier. [WARNING: Do not overheat the unit.]
7
Variable factorMoisture
Influential partElectric parts
Target conditionDamp
Service procedureWet. [WARNING: Do not directly pour water on components. Use a mist sprayer.]
8
Variable factorElectric loads
Influential partLoad switches
Target conditionLoaded
Service procedureTurn on headlamps, air conditioner, rear defogger, etc.
9
Variable factorIdle switch condition
Influential partControl unit
Target conditionON-OFF switching
Service procedureRotate throttle sensor body.
10
Variable factorIgnition spark
Influential partTiming light
Target conditionSpark power check
Service procedureTry to flash timing light for each cylinder using ignition coil adapter (S.S.T.).
NOTE
When possible, use CONSULT to perform diagnostic and service adjustment operations.